In the prior art, the technology for radioactive material inspection and the technology for vehicle/container examination with accelerators as radiation sources have been developed, and both do well in respective inspection fields.
The conventional radioactive material inspection technology usually uses the abnormal change of the system count rate caused by the radiations emitted during the object (e.g. pedestrian, package, vehicle, container and train) passes through the monitor, to inspect the radiations and know whether there is radioactive material in the object under inspection.
The vehicle/container examination system with accelerators as radiation sources is a typical radiographic system, which reflects the difference between the object's internal mass thicknesses by detecting the changes of the intensity of X/γ radiations which penetrate the object. As for the radiation sources of the container examination system, there are three kinds, i.e. radioactive isotopes, X-ray machines and accelerators. Most countries of the world employ such kind of radiographic system to inspect smuggle and security of vehicle/containers due to the advantages such as strong penetrability etc. of the radiographic system which uses an accelerator as the radiation source.
The radiographic examination and the radiation inspection both are used at the customs, the borders and important gateways to achieve security inspection. So, there is a need for an integrated technology to quickly inspect radioactive materials while doing radiographic examination such that the affect on the legal trade currency tightly relevant to the state economy can be reduced as much as possible.
However, when the vehicle/container examination system is examining vehicle/containers by using an accelerator as the radiation source, the accelerator will emit a lot of X/γ radiations while the radiation monitor just determines whether there is radioactive material in the object under inspection by detecting radiations. Consequently, when the radiographic examination system and the radiation monitor are combined simply, the radiation monitor will be interfered by X-rays when doing radiographic examination.